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[CF-metadata] GIS versus CF conventions

From: Bryan Lawrence <b.n.lawrence>
Date: Wed, 31 Aug 2005 09:59:57 +0100

Hi Folks

(this email sent without engaging brain ...)

the issue of including coordinates or excluding them will become seriously
difficult once we have adaptive grids ...

(in what follows it = georeferencing info).

CFwise: I think the bottom line is that we have two cases, 1) where we can and
should put it in the file, and 2) where we can't or wont put it in the file.
Both should be supported, but either case we can encode it in exactly the
same way but effectively use a pointer. This is now allowing axis
information to be outside the file, but I think as everyone is implying
aggregation can support this. Arguably we have this requirement now, because
we can legally put just zonal wind in a single file and meridional wind in
another, but one might argue that software trying to construct wind vectors
will want both and fail if they're not in the same file. What we need is a
standard way to say for any given parameter axis or whatever that (this other
parameter, axis or whatever) is relevant to it. So we need both a) controlled
relationship types and b) a pointer class ...

On the WCS side: WCS will need to support auxillaries of this nature in the
future. One anticipates downloading first the coordinates, and then for
subsequent calls on the same subdomain, just downloading the data. This of
course requires some state to be held at the WCS ... so it's not doable
easily now.

I can't see how we can avoid this.

Cheers
Bryan


On Tuesday 30 August 2005 16:16, Jonathan Gregory wrote:
> Dear Magi
>
> > in the case of staggered grids having two lat/lon grids which are
> > off-set by half the grid resolution is somewhat silly.
>
> I don't think so. It means that plotting/processing applications which can
> interpret auxiliary coordinates will be able to use the data. I am sure
> that there will be far less software having the capability to interpret map
> projections and other grid descriptions (yet to be defined). To make the
> metadata as useful as possible, it has to be given in simple terms.
>
> Cheers
>
> Jonathan
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://www.cgd.ucar.edu/mailman/listinfo/cf-metadata

-- 
Bryan Lawrence
Head, NCAS/British Atmospheric Data Centre
Director, CCLRC/Environmental Data Archival and Associated Research
badc.nerc.ac.uk, home.badc.rl.ac.uk/lawrence, +44 1235 445012
(CCLRC, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX)
Received on Wed Aug 31 2005 - 02:59:57 BST

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